Transferring photographic prints from separate supports to a single support.



P D. BREW/ST TRANSFERRING PHOTOGRAPHIC PRINTS FRQTWSEPARATE SUPPORTS TOA SINGLE SUPPORT.

APPLICATION FILED JUNET, 1916.

Patented. May 1, 1917.

WITNESS M ATOM/Era tree STATES PATENT canton,

PERCY DOUGLAS BREWSTER, OF EAST ORANGE, NEW JERSEY.

TRANSFERRING' PI-IOTOGRAPHIO PRINTS FROM SEPARATE SUPPORTS TO A SINGLESUPPORT.

Application filed June 7, 1916.

To all whom it may concern:

Be it known that I, PERCY D. BREWSTER, a citizen of the United States,residing at East Orange, county of Essex, and State of New Jersey, haveinvented certain new and useful Improvements in TransferringPhotographic Prints from Separate Supports to a Single Support, of whichthe following is a full, clear, and exact description.

In a method of making photographs in natural colors which has met withconsiderable success the practice. is to make at least two negatives ofthe object, one recording the image of the object by light of one coloror group of spectral colors and the other recording the image in lightof another color or color-group. From these negatives (one of which isreversed from right to left) positive prints on glass or celluloid aremade, which positives are then treated in any convenient manner to coloror stain the images in two different colors. For example, if onenegative is made through a red filter or screen, so as to record theaction of light predominantly red in color, and the other through agreen filter for a like purpose, the positive image from the rednegative is stained green and the one from the green negative is stainedred. The stained positives are then superposed face to face, in registrywith each other, with the result that when the positives thus combinedare viewed by white light passing through both they will exhibit theobject in substantially its natural colors.

The two colored positives or transparencies described can be boundtogether permanently, like a lantern-slide and its coverglass, but formany purposes it is desirable to strip one of the glasses off; or evento remove both glasses and transfer the two colored films or emulsionsto a flexible support, as for example opaque white paper or celluloid sothat the completed picture can be handled without danger of breakage.This is especially desirable in the case of pictures of large size, sayeight by ten inches and larger? The present invention relates to thisfeature of the process, and'its chief object is to provide a method bywhich the emulsions can be stripped from two or more plates withoutappreciable contraction or expansion of the emulsion films so as notSpecification of Letters Patent.

Patented May l, 191?.

Serial No. 102,170.

to interfere with the exact registry of the two images. Another objectis to provide an effective method by which exact registry of the twoimages can be quickly obtained. To these and other ends the inventionconsists in the novel process and steps hereinafter described.

In the accompanying drawing, Figures 1, 2, 3 and 4 are sectional viewsillustrating four stages of the process.

In practising my method or process in the preferred manner one or theother ofthe two positive plates 2, 4, is immersed in a suitablestripping solution by which the gelatin composing the film (1 or 3 inthe drawing) is hardened and loosened so that it can be stripped offfrom its plate or support. Preferably a solution or bath of thefollowing composition is used, at ordinary room temperature:

Solution A.

Potassium carbonate 9grams. Formaldehyde, 37% 9cc. Glycerin 900. Water10000.

If the print is on glass, immersion for twenty minutes in the above bathwill usually suffice. If it is on celluloid I prefer to immerse it forsay five minutes in each of the following solutions, in success1on:

It is to be understood that wide variation in the stripping solutionsused is permissible. The above solution A. works well with hammertransparency and lantern-slide plates. For other plates, formulae usingsodium fluorid may be employed.

After immersion in the stripping solution the excess is wiped off. I

The other plate, previously treated in any convenient manner to hardenthe emulsion, as for example with the usual formalin or formaldehydebath, is coated with a suitable adhesive or cement capable of hardeningor tween 100 and 104. Preferably the plate itself is also heated to thesame or slightly higher temperature to prevent too rapid setting orhardening of the gelatin layer.

The two plates are now placed face to face and shifted about withrespect to each other until the two images are in registry, the operatorholding the two plates be p tween himself and a source of light so as tosee the work clearly. The fluid gelatin layer between the two platespermits of easy sliding movement of one plate on the other, so thatregistry can be secured in a few seconds; In the drawing 5 designatesthe layer of gelatin, and Fig. 1 shows the two plates at this stage ofthe process.

The two plates are now held firmly together, as by means .of a weight,to allow the intermediate gelatin layer to set. From thirty minutes toan hour will usually be found suflicient time to secure the desiredhardening or setting. In warm weather. the plates can be chilled withice. In fact strong cooling of the plates (of course after they havebeen brought into registry) is advantageous at any time, as it shortensthe period of setting. After the gelatin has set, the plate that wastreated with the stripping solution can be readily lifted off, leavingits emulsion firmly cemented to the face of'the other plate. This stageis illustrated in Fig. 2 of the drawing.

The plate bearing the two emulsions is now immersed in the strippingsolution, the same solution as used before but diluted to four or fivetimes its original bulk with water,-.1fter which it is coated with asuitable cement, for example the ten per cent. gelatin solutionrecommended above. The final support 6, Fig. 3, say, a piece of strongwhite paper or a sheet of opaque white celluloid is then pressed firmlyon to the plate and the cement allowed to set, after which the paper orcelluloid support 6, bearing the two emulsions 1, 3, united to eachother by the cement layer 5 and -to said support by the cement layer 7,can be peeled or stripped off the plate 1 as indicated in Fig. 4. Itwill be observed that the print will or will not be reversed on thefinal support 6 according as one plate or the other was the one that wasfirst to be stripped. Thus, if in Fig. 1 the image is seen correctlywhen viewed from the right of the figure, plate 2 should be stripped offfirst, and the image will then be correct on the final support 7 Ifplate 1 had been stripped off first the image on the paper or celluloid7 would be reversed.

Any colloid or cement can be used that will set (without drying) to asuificient ex- -plate 2 was. be applied as described above.

In three-color work the third plate (not shown) is treated with thestripping solution and then cemented to the emulsion 1, Fig. 2, afterwhich it is stripped off as The final support 6 can then It ispreferable, as stated above, that one negative be reversed, right toleft, with respect to the other, so that direct prints therefrom can beput in registry face to face, just as a persons hands can be put intoregistry palm to palm. Ifnot, a reversed image will have to be madefromone of them or one of the prints will have to be transferred to anintermediate temporary support before applying it to the other print. Inthe former course, which is in general preferable, a convenient methodis simply to transfer the emulsion film face down to another glassplate. Prints can then be made from it which will register with printsfrom the other negative.

It is to be understood that the invention is not limited to the specificdetails herein described, as the same can be varied without departingfrom the spirit of the invention.

I claim:

1. The method of treating photographic prints on transparent supports,comprising treating one of the prints to toughen the emulsion and loosenthe same from its support; coating the face of such print with asuitable cement or adhesive capable of setting without drying; placingthe other print,

'face down, upon and in registry with the first print and allowing thecement to set;

removing the transparent support of the first print whereby itsemulsion-film is left on the emulsion-film of the other, the two forminga combined print; treating the combined print to toughen the loweremulsionfilm and loosen it from its support; and transferring the twoemulsion-films to a permanent support.

2. The method of treating photographic prints to transfer the same fromseparate supports to a single flexible support, comprising treating oneof the prints to toughen and loosen its emulsion-film; cementing theother print on the first, face to face; removing the support of thefirst emulsion-film, leaving the two films on the support of the secondfilm, treating the latter to toughen the same and loosen it from itssupport; and transferring the two films to a permanent flexible support.

3. The method of treating photographic color prints to transfer the samefrom separate rigid supports to a single flexible support such as opaquewhite celluloid or paper,

comprising treating the first print to toughen its emulsion-film andloosen the same; cementing the other print upon the first, face to face,With a cement capable of setting without drying; removing the firstsupport, leaving the two emulsion films cemented together on the secondsupport, forming a combined print; treating the combined print totoughen the underlying emulsion film and loosen it from the rigidsupport; cementing the desired permanent flexible support to theuppermost emulsion-film of the combined print; and stripping off theflexible support with the two emulsion-films cemented to it.

4. The method of treating photographic color prints to transfer the samefrom separate rigid supports to a single flexible support, comprisingtreating the first print to toughen and loosen its emulsion film;coating its emulsion film with a cement contain- 'ing gelatin; applyingthe second printto the, first, face to face, and allowing the cement toset; removing the rigid support of the first print, leaving the twoemulsion films on the second support to form a combined print; treatingthe latter to toughen the underlying emulsion-film and loosen the samefrom its support; coating the face of the combined print with a suitablecement; applying the desired permanent flexible support to the face ofthe combined print and allowing the same to adhere firmly thereto; andstripping off the flexible support with the two emulsion films adheringto it.

In testimony whereof I hereunto afiix my signature.

PERCY DOUGLAS BREWSTER.

